This invention relates to laryngeal mask airways and their manufacture.
It is common practice to use an airway known as a laryngeal mask for administering anaesthetic and ventilation gases to a patient. These airways comprise a tube with an inflatable mask or cuff at one end, the tube being inserted in the patient""s mouth so that one end is located in the hypopharynx and so that the mask forms a seal in this region with the surrounding tissue. Laryngeal masks are described in, for example, U.S. Pat. Nos. 5,355,879, 5,305,743, 5,297,547, 5,282,464, GB 2267034, U.S. Pat. No. 5,249,571, 5,241,956, 5,303,697, GB 2249959, GB 2111394, EP 448878, U.S. Pat. No. 4,995,388, gb2205499 GB 2128561 and GB 2298797.
Laryngeal masks have several advantages over endotracheal tubes, which are longer and seal with the trachea below the vocal folds. It can be difficult, however, to manufacture the patient end of the mask at low cost.
It is an object of the present invention to provide an improved laryngeal mask assembly and method of manufacture.
According to one aspect of the present invention there is provided a laryngeal mask assembly comprising an elongate tube and a mask portion at the patient end of the tube, the mask portion including a mount member of generally elliptical shape having an opening therethrough communicating with the patient end of the tube and a hollow cuff member extending around the mount member, the cuff member being formed integrally from the mount member.
The mount member and the cuff member are preferably made from the same thermoplastic material, the cuff member being blow moulded with a thinner wall than the mount member. The mask portion may include an inflation tube extending along a groove in the mount member. The assembly preferably includes a retaining plate arranged to retain an edge of the cuff member. The mask portion may include a plurality of surface formations, such as ribs, arranged as epiglottis guides. The cuff member may contain a resilient foam.
According to another aspect of the present invention there is provided a method of manufacture of a laryngeal mask assembly including the steps of providing an elongate tube having a mount member at its patient end, the mount member being of generally elliptical shape and having an opening therethrough communicating with the patient end of the tube, and forming from the material of the mount member a hollow cuff member extending around the mount member.
The mount member and the cuff member are preferably made from the same thermoplastic material, the cuff member being blow moulded with a thinner wall than the mount member. The method preferably includes the step of sealing an edge of the cuff member with the mount member by means of a retaining plate. The mount member may either be preformed prior to being placed in a mould tool for blow moulding of the cuff member or the mount member may be moulded in a cavity, the cavity then being enlarged and the cuff member being subsequently blow moulded in the enlarged cavity.
According to a further aspect of the present invention there is provided a laryngeal mask assembly manufactured by a method according to the other aspect of the present invention.
A laryngeal mask airway assembly and its method of manufacture, according to the present invention, will now be described, by way of example, with reference to the accompanying drawings.